On one recording medium such as a DVD (Digital Versatile Disc), which has been recently developed, a large capacity of data for one movie can be recorded as digital information. When video information and so forth can be recorded as digital information, it will become important to protect copyright of digital information against illegal copies.
In DVD-Video, as a copy protection technology, CSS (Content Scrambling System) has been employed. The use of the CSS is permitted for only DVD mediums, not recordable DVDs such as a DVD-R, a DVD-RW, DVD+R, DVD+RW, and so forth due to CSS contract. Thus, the CSS contract does not permit the user to copy the contents of a DVD-Video disc to a recordable DVD (so-called bit-by-bit copy).
However, there was a serious situation of which the CSS encrypting system was broken. Illegal software called “DeCSS” that easily decrypts contents that has been encrypted in accordance with the CSS encryption system and copies the decrypted contents to a hard disk was published on the Internet. As a background of the advent of “DeCSS”, reproduction software was designed with a CSS decryption key that was not anti-tampered although it was supposed to be anti-tampered. The reproduction software was reverse-engineered and the encryption key was decrypted. As a result, all the CSS algorithm was decrypted.
As a successor of the CSS, CPPM (Content Protection for Pre-Recorded Media) as a copyright protection technology for DVD-ROMs such as a DVD-Audio disc and CRPM (Content Protection for Recordable Media) as a copyright protection technology for recordable DVDs and memory cards have been proposed. In these systems, even if there is a problem about encryption for contents, storage of management information, and so forth, the systems can be updated. Even if data of a whole disc is copied, the reproduction can be restricted. A method for protecting copyright for DVDs is described in the following non-patent related art reference 1. The CRPM is described in the following document distributed by its licenser, 4C Entity, LLC, USA.
“Spreading-out Copyright Protection Space Starting from DVD”, Yamada, Nikkei Electronics, pp. 143-153, 2001. 8. 13.
“Content Protection for Recordable Media Specification DVD Book”
Under a personal computer (hereinafter, sometimes abbreviated as PC) environment, since a PC and a drive are connected with a standard interface, secret data may be leaked out or tampered at the standard interface. As a result, there is a risk of which application software may be reverse-engineered and secret information may be stolen or tampered. Such a risk hardly occurs in an electronic apparatus that has a recording and reproducing apparatus that is integrated thereinto.
When a copyright protection technology is implemented to an application program that is executed on a PC, to prevent the copyright protection technology from being analyzed, the application program is generally anti-tampered. However, there is no index that represents the strength of tamper-resistance. As a result, countermeasures against reverse-engineering depend on the decision and capability of each implementer. As a result, the CSS was broken. With respect to the copyright protecting technologies CPPM for DVD-ROM and so forth and CRPM for recordable DVDS, where were proposed as a successor of the CSS, an engineering method that allows a problem about implementation of software to a PC to be solved has not been proposed.
An object of the present invention is to secure the safety of a copyright protecting technology under the PC environment. In other words, an object of the present invention is to provide a recording and reproducing apparatus, a data processing apparatus, and a recording, reproducing, and processing system that prevent a drive that is not validly licensed from being produced and that allow it to be securely revoked.